Grain dryer



1967 J. D. BUSSELL ETAL GRAIN DRYER Filed May 12. 1964 w Mm Q5 mwmm m M?5 i aww fa @MW United States Patent C) 3,300,873 G DRYER Jack D.Russell, Peoria, Walter P. Dickens, Eureka, and

Frank N. Eidsvoog, East Peoria, 111., assignors to Hart- Carter(Iompany, Minneapolis, Minn, a corporation of Delaware Filed May 12,1964, Ser. No. 366,781 8 Claims. (Cl. 34168) Our invention relates tograin dryers and more particularly to an improved rack type grain dryerhaving air intake and exhaust members through which tempered air iscirculated to pass through the grain with a greatly increased velocityof air flow to improve drying efliciency while preventing particles ofthe grain from being discharged at the air outlet.

Grain dryers and rack type grain dryers specifically have been wellknown and in use :for some time. In drying apparatus of this type, asource of drying air which may be tempered is circulated through thegrain or granular material and discharged from the dryer at a pointapart from the outlet for the grain. Efiiciency of the dryer and itscapacity is for the most part limited by the velocity of the flow ofdrying air through the grain and the design of the racks through whichthe drying air and the exhaust air passes. As velocity of air fiowthrough the dryer increases above a normal point, the granular materialis picked up by this air flow and discharged at points other than thegrain outlet of the dryer resulting in loss of granular material andincreasing dust discharge from the same.

The present invention is directed to an improved grain dryer whichutilizes improved intake and exhaust racks to provide for betterdistribution and movement of the grain through the tower of the dryer,while increasing the velocity of drying air therethrough to increase theefficiency of drying and at the same time prevent grain and dust frombeing discharged from the air discharge of the dryer. This improvedgrain dryer may be utilized with tempered air, 'both heated and cooled,to obtain maximum drying efficiency. At the same time, the design of theexhaust rack permits a considerably increased velocity of drying air tosubstantially reduce drying time and increase the dryers capacity todry. The improved rack of the tubular members incorporated therein areperforated in such a manner and positioned relative to one another toprovide for maximum dis tribution of the drying air. The flow of thegranular material across the drying rack and tubular members thereinwipes granular material from the perforations in the tubular members toprevent obstruction to air flow and insure uniform drying of the grain.

It is therefore an object of this invention to provide an improved graindryer.

Another object of this invention is to provide in an improved graindryer, an improved exhaust rack which facilitates an increased volume ofair flow through the dryer.

A further object of this invention is to provide in an improved airdryer an exhaust rack which prevents blowing of the grain and dust fromthe grain through the air discharge.

A still further object of this invention is to provide an improved airdryer with an exhaust rack having tubular duct members with perforatedbottoms which permit uniform distribution of the drying air through thegrain drying tower and the grain therein while facilitating movement ofthe grain through the tower from the inlet to the outlet thereof toincrease the efiiciency of the drying operation.

Another object of this invention is to provide an air duct constructionwhich may be readily formed and 3,3@,873 Patented Jan. 31, 1967 mountedin rack form to provide a simplified intake and exhaust rack structurefor a grain drying tower.

A still further object of this invention is to provide an improved graindryer which is simple in design and economical to construct and maintainand which greatly increases the efiiciency of drying.

These and other objects of this invention will become apparent from areading of the attached description together with the drawings wherein:

FIGURE 1 is a side elevation view of the improved grain dryer;

FIGURE 2 is a front elevation view of the improved grain dryer;

FIGURE 3 is a sectional view in partial perspective of the grain dryertaken along the lines 3-3 of FIG- URE 1;

FIGURE 4 is a perspective view of an intake tube portion of an intakerack showing constructional details of the same;

FIGURE 5 is a perspective view of an exhaust tube portion of an exhaustrack showing constructional details of the same;

FIGURE 6 is a perspective view of an exhaust tube positioned adjacentthe edge of the tower in the edge Olf an exhaust rack;

FIGURE 7 is a sectional view of the tube of FIGURE 6 taken along thelines 7-7 therein; and

FIGURE 8 is a perspective view of an alternate embodiment of a tube forthe improved grain dryer.

The improved grain dyer of the present invention is of the rack typewhich utilizes improved designs of the intake and exhaust tubes tofacilitate an increased volume of drying air through the granularmaterial or grain to be dried within a tower. Thus in FIGURES 1 and 2,there are shown schematically a drying tower, indicated generally at 10,which tower houses a plurality of racks therein identified as exhaustracks 12 and intake racks 14 positioned in alternate layers throughoutthe extent of the tower. As will be seen in FIGURE 1, the tower has aninlet section 15 at the top thereof with an inlet port 16 therein intowhich grain is introduced for drying purposes. The term grain as usedherein applies to corn,

wheat, and all small grains in which it is desired to remove themoisture to prevent spoilage in processing or storage. The improvedgrain dryer in addition to the inlet section 15 and the plurality ofracks 12 and 14 forming the main structure of the tower includes a grainflow discharge section, indicated generally at 20, with a dryerdischarge outlet port 22 at the bottom thereof. The actual details ofthe inlet section 15 are omitted since these may take varying forms andit will be understood that any storage or distribution unit at the topof the drying tower capable of storing and distributing grain throughthe drying section of the tower may be utilized. Further, the grain flowdischarge regulating section 20 and the discharge port 22 are shownschematically since their details form no part of the present inventionand varying types of apparatus may be utilized for this purpose. The

drying section normally includes a section of the racks through whichthe drying air is circulated, such as warm air, and FIGURE 1 showsschematically an air duct 25 connected to a circulating source 27 ofwarm air which terminates in a bonnet or plenum section 26 along theside of the tower for the purpose of directing tempered or warm airthrough a portion of the extent of the tower or the air intake andoutlet racks. Further, in FIGURE 1, a source of cooling air is directedthrough a cooling portion or section of the intake and exhaust racks ofthe extent of the dryer tower, this source being shown at 30 andincluding an air duct 32 extending to a cooling air bonnet 33 at theside of the tower to cool the warmed grain as it is dried prior to thedischarge through the discharge section 20. The details of the airtempering apparatus are also omitted for simplicity, and it will beunderstood that varying forms of this apparatus may be utilized in thedrying tower. As will be seen in FIGURES 1 and 2, the tower is generallysquare in horizontal cross section and is sealed or formed solid at twosides thereof, such as is indicated at 40, with the remaining two sidesproviding the air intake and exhaust for the drying and cooling air ofthe dryer. Thus, as is shown in FIGURE 1, the side surface of the tower44 represents the air intake side While the opposite side surface suchas is indicated at 45 and shown in elevation view in FIGURE 2 representsthe air discharge section of the tower having 'a plurality of dischargeapertures or holes 46 therein, as will be hereinafter more fullydescribed.

The sectional view of FIGURE 3 shows a partial cross section of theinterior of the drying tower and the relationship between tubularmembers or ducts 52, 54 of the intake and exhaust racks 14, 12respectively. It will be understood from FIGURES 1 and 2, that there area plurality of intake and exhaust racks extending along the verticalextent of the rectangular shaped or square tower, each rack beingdisposed substantially horizontal and having a plurality of parallelextending tubular members or ducts extending from the intake to theexhaust or air outlet side of the tower. Each rack contains a pluralityof tubular ducts which are spaced apart and parallel to one another andpositioned in between or aligned vertically with the spacing betweenducts in the adjacent racks. These create air flow patterns such as isindicated by the lines 56, 57 which indicate the direction of air flow:from an intake duct around the edges around the bottom of the same andaround the edges or sides of the duct up or down through the granularmaterial within the tower to the bottom portion of the verticallyadjacent rack in the exhaust section. As will be hereinafter defined,the actual constructions of the intake and exhaust racks may vary inaccordance with varying versions or embodiments of the presentinvention. Thus, as will be seen in FIGURES 1, 2 and 3, the racks intheir staggered relationship with respect to the racks above and belowtend to mix the grain or granular material as it is allowed to flowthrough the grain tower. The racks have holes or apertures at oppositeends respectively so that all of the intake holes relative to the intakeduct members 52 are present or open to the plenums 26, 33 adjacent theside of the tower to provide for introduction of tempered air throughthe tower. These ducts are normally enclosed on the top and sidesthereof but open at the bottom as will be best seen in FIGURE 4. Thus,each tubular member forming the intake rack 14 is identical to thesingle tubular member shown generally at 52 in FIGURE 4. It is comprisedof a V shaped member 60 Whose top sides are approximately 45 from thehorizontal with parallel extending sides therefrom, such as is indicatedat 64, which have no bottom connecting part. This tubular member may beformed of sheet metal and includes tabs 65 at the extremities thereofwhich fit through cooperating slots in rectangular or square end plates66, 68 having flanges 67 thereon with the tabs being crimped over to fitthe end plates to the tubular member 60. As will be seen in FIGURE 4,the end plate 66 is solid such that the tubular member 60 is closed atthis extremity While the end plate 68 has an aperture 70 therein. Aplurality of such tubular members are positioned in side by siderelationship and suitably interconnected through the flanges 67 of theend plates by suitable means, such as screws (not shown), to form therack 14 extending across the rectangw lar tower. The angle of the top ofthe tubular member 60 may vary slightly but it will be greater than thenormal angle of repose of the various grains or granular materials to bedried in the tower.

The tubular members 54 forming the exhaust rack 12 are shown in oneversion in FIGURE as incorporating a top V shaped member 72 and a bottomV shaped member 74 which members are positioned together with the sidesof the top member overlying the sides of the bottom member to form acomplete enclosure. These members are connected respectively throughtabs 7 6 thereon to end caps 78, 80 having flanges 82 thereon. As willbe seen in FIG- URE 5, the bottom V shaped member includes a pluralityof perforations extending throughout the entire extent of the same, suchas indicated at 85. In the assembled relationship of the tubular member72, 74 with the end caps 78, 8d, a complete tubular member is formedwhich is closed at the bottom except for the perforations 85 in thelower or bottom V shaped member 74 which extend up through the sides ofthe same to the edge of the upper V shaped member 72. End cap 80 issolid or closed closing the resulting tubular member 54 at this pointand the end cap 78 has the aperture 45 therein which is shown as exposedto the exhaust side 45 of the tower. The exhaust rack 12 of the tower ismade up of a plurality of the tubular members or ducts 54 which areconnected together in a side by side relationship through suitablesecuring means attached to the flanges or through the flanges 82 thereofto form an assembled exhaust rack.

FIGURE 6 shows a perspective view of the end ducts of the exhaust rackwhich are one half the size of the center ducts, as will be evident fromthe disclosure in FIGURE 2. In this construction, as is shown by thesectional view of FIGURE 7, half of the generally diamond shaped memberis formed by the equivalent of one half of an upper and lower V shapedmember for the duct member 54 with the lower half of the same includingthe perforations or apertures 85 therein. The end caps 90, 91 for thisduct member, which is identified at 94, are respectively open with anaperture 46 and closed at the opposite extremity to provide the samepassage as in the duct members 54. The half ducts at the edges or theends of the racks provide the desired spacing vertically with respect tothe intake ducts to provide the staggered relationship of intake andexhaust duct members which give a maximum circulation of air through thegranular material in the tower.

The physical size of the apertures or perforations 85 in the exhaustduct members in this embodiment of the in= vention, are such that theapertures 85 are smaller than the size of the grain or granular materialbeing dried in the tower. Further, the total cross sectional area of allof the apertures or perforations along the bottom of a duct member 54 or94, that is in the V shaped member 74 or half member forming the same,will be greater than the cross sectional area of the aperture 46 in theend plate 78 or 90 such that these apertures will not cause anysubstantial restriction to air flow through the duct. In addition, thesizing of the apertures 85 are such that with the desired velocity ofthe drying air through the grain, no grain 1 and very little dust fromthe grain will be carried through exhaust apertures or holes 46 to theatmosphere through the surface of the tower 45. Similarly, the angle ofthe bottom V shaped member 74 of the exhaust tubular members or ducts 54may be substantially the same as the top members or slightly less thanthe angle that the top V shaped members make to the horizontal. Thegrain flowing through the tower due to the continuous movement of thesame and its moisture content will provide for exerting a pressure onthe V shaped pre-forrned steel tubular structures to wipe the surfaceclean, keeping the perforations o1 apertures from being plugged by thegrain particles.

Thus, the exhaust duct permits an increased volume of drying air flowthrough a given quantity of grain to decrease the drying time of thesame. The open intake ducts permit a uniform flow of air through thegrain as indicated by the arrows or lines 56, 57 in FIGURE 3 to theexhaust ducts 54 and 94 which air flow will pick up moisture from thegranular material and exhaust it to atmosphere without removing thegrain from the tower or blowing dust or particles in the grain throughthe exhaust ducts 54, 94 to atmosphere.

In the preferred embodiment of the present invention,

the warm drying air is transmitted through the intake racks 14 or thetubular ducts 52 thereof by virtue of the holes 70 in the ends of theducts or the caps 68 forming the same to allow the air to travel alongthe extent of the V shaped duct member 60 and through the grain orgranular material to the vertically adjacent exhaust racks. This airflow will enter the exhaust duct members through the perforations 85therein carrying the moisture away from the grain, which moisture ladenair will be exhausted through the exhaust ports or holes 46 in thesurface 45 of the tower. The volume of air that can normally be forcedthrough the grain to remove the moisture from the grain is normallyrestricted by the velocity of the air as it leaves the grain and isexhausted through the exhaust opening. In prior air dryers, this maximumvelocity for different grain materials aud dryer designs was limited tovthe range under 3,000 feet per minute. At velocities above thesefigures, the grain became airborne and was blown out of the dryer. Withthe present invention and the specific design of the exhaust racks, theenclosed exhaust tubular members 54, 94 with the perforations orapertures 85 therein prevent the discharge of grain or particles thereofthrough the exhaust ducts to atmosphere while permitting a substantiallyhigher velocity of drying air through the grain to reduce drying timeand to remove more moisture. Since the total open area of all of theopenings or the perforations 85 in a single rack are sufficientlygreater than the area of the exhaust holes 46 in a rack, theperforations do not offer any substantial restriction or resistance tothe drying air flow through the grain. The tubular members are V shapedat such an angle that the flow of the granular material will followalong the sides of each of the tubular members uniformly distributingthe grain flow for maximum drying efiiciency and at the same timeproviding for movement of the grain across the perforations to preventplugging of the perforations or apertures 85. The cooling section of thetower provides for a cooling of the grain as it moves through the dryerto prevent spoilage and the discharge section as well as the intakesection provide for uniform flow and distribution of the grain throughthe drying racks of the tower.

An alternate construction for an intake rack 14 replaces the ducts 52with an identical design of that of the exhaust rack using tubularmembers 54. Thus as an alternate construction, the tubular membersforming the intake and exhaust racks 14, 12 would both be completelyenclosed except for the perforations on the bottom of the tubular ductswhich perforations would be of such size as to retain the grain fromentering the exhaust ducts to be discharged to atmosphere while offeringsubstantially no impedance or resistance to drying air flow, eitherheating or cooling in the tower.

As a still further alternate embodiment of the improved air dryer, anexhaust duct 97 may be formed as shown in FIGURE 8, with two V shapedmembers 72', 74' having perforations 98 in both the top and bottom Vshaped members to allow for a still greater flow of air into the exhausttubular members. In this embodiment, the apertures or perforations 98would be smaller than the size of the granular material and be uniformlydistributed along the extent of the tubular member. Grain flow acrossthe same by virtue of the vertical movement of the grain from the inletport 16 to the outlet port 22 of the tower would provide a wiping actionacross the perforations to prevent plugging of the perforations orapertures therein. This construction would be also utilized for theintake duct members in the intake racks 14 of the tower. When both theintake and exhaust ducts are formed in the manner of the duct shown at97, a slightly different air flow pattern is provided inasmuch as theintake air can be exhausted from the tubular member through theperforations 98 therein in all directions and will be received byvertically adjacent tubular members in accordance with and in proportionto the resistance to flow of the drying air in the grain.

In the preferred construction of the improved grain dryer, the ductmembers of the intake and exhaust racks 14 and 12 are formed from sheetmetal material through a conventional cutting and bending operation andattached to similarly formed end ca s to provide the as= sembled ductmembers. Such duct members may be assembled to exhaust and intake racksmerely by positioning the same in a side by side relationship andconnecting the respective end caps through their flanges throughsuitable means. Similarly, the tower construction may be completed bythe attaching of intake and exhaust racks through the flanges of the endcaps to provide a complete structure of alternate intake and exhaustracks with the intake and exhaust apertures or holes positioned onopposite surfaces thereof. A tower so assembled is fed by an air plenumconnected directly to a tower frame. The exhaust side of the tower mayinclude a suitable wall portion with accompanying apertures, or theexposed ends of the racks with the holes 46 therein. The various ductconfigurations, that is the shape of the duct and the respective openand closed constructions, will provide for increased air flow above thatnormally obtainable in present day dryers to increase drying efficiencyin the drying tower.

In considering this invention it should be remembered that the presentdisclosure is intended to be illustrative only and the actual materials,constructional details and the variations in form of the same areintended to be illustrative only. Therefore the scope of the inventionshould be determined by the appended claims.

We claim:

1. A dryer for granular material having a tower with an inlet port atthe top thereof and an outlet port at the bottom thereof and a pluralityof racks of tubular members uniformly spaced between said inlet andoutlet ports and adapted to convey drying air into and out of said towerand through the granular material which is moved in the tower from theinlet port to outlet port, the improvement comprising duct members incertain of said racks forming exhaust ducts for the drying aircirculated through said tower, said duct members in said exhaust racksbeing formed of a pair of V shaped elongated members positioned to formV shaped tops and bottom and with parallel sides, a plurality ofapertures positioned along the bottom V shaped elongated members whichapertures are smaller than the size of the granular material which flowsthrough said tower from the inlet to the outlet port thereof, andaperture means at one end of each of said duct members forming exhaustports in which the cross sectional area of the aperture is less than thetotal cross sectional area of all of the apertures in a bottom V shapedelongated member.

2. The structure of claim 1 in which the duct members in the exhaustrack include end caps to which the V shaped elongated members areattached to form the enclosed tubular structure and with one of the endcaps having the exhaust port therein and in which the end caps haveflanges to permit adjacent duct members to be connected to one anotherto form the exhaust rack with the tubular members being uniformly spacedapart and parallel to one another.

3. The structure of claim 2 in which the V shaped members forming theduct members of the exhaust rack are shaped to distribute flow of thegranular material uniformly to both sides of the duct member as thegranular material flows past the exhaust rack.

4. A dryer for granular material comprising, a rectangular tower havingan inlet port at the top thereof and an outlet port at the bottomthereof, a plurality of horizontal racks positioned across the towerbetween two sides thereof and spaced vertically from one another, eachof said racks containing a row of parallel spaced duct members with theduct members of each row being spaced between duct members in adjacentrows, each of the duct members in a rack being closed at the sameextremity with alternate rows being closed at opposite extremities toprovide respectively intake and exhaust racks of duct members, plenummeans connected to one side of said tower and in common with the intakeduct racks to discharge tempered air into said duct members of theintake racks, the duct members in the exhaust racks on the adjacent rowswith their ends closed to said plenum being opened at the oppositeextremity through the opposite side of said tower to form air dischargeopenings for the exhaust racks, all of said duct members having topsshaped to distribute flow of granular material substantially uniformlyto both sides of said duct members, and the duct members forming the airdischarge ducts in the exhaust racks being completely enclosed withinthe tower and having a plurality of apertures along the bottom surfacethereof which apertures are smaller than the size of the granularmaterial adapted to flow through said tower from said inlet to saidoutlet port, the total area of the plurality of apertures in each ductmember in each of the exhaust racks being greater than thecross-sectional area of the discharge opening at the end of each ductmember in the exhaust rack, said duct members in the exhaust racks beingformed of two V shaped members connected together at their outer edgesto form V shaped tops and bottoms with parallel sides in between andwith the angle of V shaped design to the horizontal being bottom of theexhaust duct members are small enough in size as to preclude theentrance of grain material therein but large enough to offer noappreciable additional resistance to air flow from said inlet ducts toatmosphere.

6. The dryer of claim 5 in which the duct members are formed of thinsheet metal material bent to form V shaped configuration in the ductmember.

7. The dryer of claim 6 in which the exhaust duct members adjacent theopposite side Walls of the tower remote from the plenum and the openingsin the exhaust racks are half ducts.

8. The dryer of claim 6 in which the V shaped members forming thetubular members are connected to end caps in which one end cap has anaperture therein and the other end cap is closed to form the completedduct member and in which the end caps are attached to one another toform the racks extending across the tower.

References Cited by the Examiner UNITED STATES PATENTS 1,028,899 6/1912Morris 34-170 1,196,979 9/1916 Randolph 34174 1,346,335 7/1920 Randolph3417O 1,623,553 /l927 Randolph 3417O X 1,685,338 9/1928 Randolph 34-1702,701,920 2/1955 Campbell 34170 X DONLEY J. STOCKING, Primary Examiner.

FREDERICK L. MATTESON, IR., Examiner.

C. R. REMKE, Assistant Examiner.

1. A DRYER FOR GRANULAR MATERIAL HAVING A TOWER WITH AN INLET PORT ATTHE TOP THEREOF AND AN OUTLET PORT AT THE BOTTOM THEREOF AND A PLURALITYOF RACKS OF TUBULAR MEMBERS UNIFORMLY SPACED BETWEEN SAID INLET ANDOUTLET PORTS AND ADAPTED TO CONVEY DRYING AIR INTO AND OUT OF SAID TOWERAND THROUGH THE GRANULAR MATERIAL WHICH IS MOVED IN THE TOWER FROM THEINLET PORT TO OUTLET PORT, THE IMPROVEMENT COMPRISING DUCT MEMBERS INCERTAIN OF SAID RACKS FORMING EXHAUST DUCTS FOR THE DRYING AIRCIRCULATED THROUGH SAID TOWER, SAID DUCT MEMBERS IN SAID EXHAUST RACKSBEING FORMED OF A PAIR OF V SHAPED ELONGATED MEMBERS POSITIONED TO FORMV SHAPED TOPS AND BOTTOM AND WITH PARALLEL SIDES, A PLURALITY OFAPERTURES POSITIONED ALONG THE BOTTOM V SHAPED ELONGATED MEMBERS WHICHAPERTURES ARE SMALLER THAN THE SIZE OF THE GRANULAR MATERIAL WHICH FLOWSTHROUGH SAID TOWER FROM THE INLET TO THE OUTLET PORT THEREOF, ANDAPERTURE MEANS AT ONE END OF EACH OF SAID DUCT MEMBERS FORMING EXHAUSTPORTS IN WHICH THE CROSS SECTIONAL AREA OF THE APERTURE IS LESS THAN THETOTAL CROSS SECTIONAL AREA OF ALL OF THE APERTURES IN A BOTTOM V SHAPEDELONGATED MEMBER.